Tunable Synthesis of Metal-Organic Chalcogenide Semiconductor Nanocrystals

Metal-organic chalcogenolates (MOCs) are crystalline solids of covalently bound hybrid organic-inorganic materials made of metal-chalcogenide cores with surrounding organic ligands. A prime example of a two-dimensional (2D) MOC is silver benzeneselenolate, which consists of sheets of AgSe with phenyl groups in between. The quantum-well-like structure of MOCs leads to advantageous optical properties, e.g., spectrally narrow fluorescence. Moreover, as MOCs remain stable under ambient conditions while avoiding toxic elements, they have been explored as an alternative to common 2D semiconductors, such as transition-metal dichalcogenides and layered perovskites. However, to pursue MOCs, simple synthetic strategies are needed to exploit the modular nature of their architecture. Here, we present a versatile synthesis that can produce Ag-based MOCs of various sizes and compositions on the gram scale. By changing our reaction conditions, we demonstrate particles with lateral sizes ranging from tens of micrometers to below 100 nm, leading to colloidal stability in polar solvents. By varying the constituent chalcogenides and organic ligands, we show that the optical properties of the resulting particles can be tuned across the visible spectrum. Due to the versatility of our synthesis, it can enable a wider investigation of MOCs, advancing their development for optoelectronic applications.